Can you see the southern lights in Ushuaia in December?

On dark, clear nights with enough activity. 31 of 31 nights at Ushuaia have civil darkness.

How dark is Ushuaia in December?

Ushuaia averages 4.7 hours of civil night a night in December 2026, from 5 h 8 min on the 1st to 4 h 43 min on the last night.

How cloudy is Ushuaia in December?

NASA POWER's 2001 to 2020 climatology gives Ushuaia's 1 degree cell 84% mean cloud in December, against 78% for the whole year. It is an all-hours average, not a forecast.

What is the best night in December 2026 for aurora in Ushuaia?

By darkness and moon alone, Dec 1, with 3 h 12 min of moon-free darkness inside 10 PM to 2 AM at Ushuaia. Activity on that date will only be known hours ahead.

Is December or January better in Ushuaia?

By civil night times the clear share, December scores 0.7 hours at Ushuaia and January 0.9. January comes out ahead.

Ushuaia · December 2026

Southern lights in Ushuaia in December 2026

Answer

December gives Ushuaia 4.6 hours of civil night on the 15th, the lightest month of its year, under 84% mean cloud.

4.7 h

civil night, average night

SunCalc for -54.81, -68.32; NASA POWER; GFZ Kp

December against the rest of the year

0.9

1.5

2.0

2.7

3.8

4.1

3.1

2.5

1.7

1.0

0.7

December cloud at Ushuaia averages 84% in NASA POWER's 2001 to 2020 record, 6 points cloudier than its yearly mean. July is Ushuaia's clearest month at 72%. By civil night times clear sky, December scores 0.7 hours at Ushuaia, 12th of 12. Buffalo, 10,909 km away, averages 85%, cloudier by 1 points.

Civil night at Ushuaia starts December at 5 h 8 min and reaches 4 h 43 min by December 31, 0.4 hours shorter. No night keeps the 10 PM to 2 AM window fully dark at Ushuaia. The sun never reaches 18 degrees down, so Ushuaia gets no astronomical night in December.

December night by night

December opens toward a new moon on Dec 8, with full moon on Dec 23, in America/Argentina/Ushuaia dates. Ushuaia gets 77 hours of civil night with the moon below the horizon across the month. The best of them for moon-free darkness inside 10 PM to 2 AM: Dec 1 (3 h 12 min), Dec 2 (3 h 10 min), Dec 3 (3 h 8 min).

1
41% lit
3.6 h
2
31% lit
3.7 h
3
22% lit
3.8 h
4
14% lit
4.0 h
5
8% lit
4.2 h
6
4% lit
4.4 h
7
1% lit
4.8 h
8
0% lit
4.8 h
New
9
1% lit
4.5 h
10
4% lit
3.8 h
11
8% lit
3.4 h
12
14% lit
3.1 h
13
21% lit
2.9 h
14
30% lit
2.7 h
15
39% lit
2.6 h
16
49% lit
2.4 h
17
59% lit
2.3 h
18
69% lit
2.1 h
19
79% lit
2.0 h
20
88% lit
1.7 h
21
94% lit
1.2 h
22
98% lit
0.4 h
23
100% lit
0.0 h
Full
24
98% lit
0.2 h
25
94% lit
0.7 h
26
87% lit
0.9 h
27
78% lit
1.1 h
28
68% lit
1.3 h
29
57% lit
1.4 h
30
47% lit
1.6 h
31
37% lit
1.7 h

Each cell is the night that starts on that date. Hours are civil-dark time with the moon below the horizon; the green rule scales with them. Green outline: new moon. Bone outline: full moon.

Activity in past Decembers

No whole Kp puts the average oval edge over Ushuaia by SWPC's rule, so the GFZ record has no threshold to count for December. Ushuaia sits at 45.6 degrees geomagnetic. The lowest NOAA storm level whose typical viewing latitude reaches it is G4 (Kp = 8, including a 9-). Even Kp 9 does not put the average oval edge overhead by SWPC's rule.

December across Argentina

Coming from November (6.2 hours at Ushuaia), December loses darkness, and the nights keep growing into January (5.5 hours on the 15th). The December solstice falls on December 21, 17:49 Ushuaia time.

Darkness and moon, every night

Ushuaia, December 2026: each night from local noon to the next noon
Night	Civil	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Tue Dec 1	5 h 8 min	3 h 36 min	3 h 12 min	41%
Wed Dec 2	5 h 5 min	3 h 42 min	3 h 10 min	31%
Thu Dec 3	5 h 2 min	3 h 49 min	3 h 8 min	22%
Fri Dec 4	4 h 59 min	3 h 57 min	3 h 6 min	14%
Sat Dec 5	4 h 56 min	4 h 9 min	3 h 4 min	8%
Sun Dec 6	4 h 53 min	4 h 26 min	3 h 2 min	4%
Mon Dec 7	4 h 50 min	4 h 50 min	3 h	1%
Tue Dec 8	4 h 48 min	4 h 48 min	2 h 59 min	0%
Wed Dec 9	4 h 46 min	4 h 27 min	2 h 39 min	1%
Thu Dec 10	4 h 44 min	3 h 49 min	2 h 1 min	4%
Fri Dec 11	4 h 42 min	3 h 23 min	1 h 35 min	8%
Sat Dec 12	4 h 40 min	3 h 5 min	1 h 18 min	14%
Sun Dec 13	4 h 38 min	2 h 52 min	1 h 5 min	21%
Mon Dec 14	4 h 37 min	2 h 42 min	55 min	30%
Tue Dec 15	4 h 36 min	2 h 34 min	47 min	39%
Wed Dec 16	4 h 35 min	2 h 26 min	39 min	49%
Thu Dec 17	4 h 34 min	2 h 18 min	32 min	59%
Fri Dec 18	4 h 33 min	2 h 9 min	22 min	69%
Sat Dec 19	4 h 33 min	1 h 58 min	10 min	79%
Sun Dec 20	4 h 33 min	1 h 40 min	0 min	88%
Mon Dec 21	4 h 33 min	1 h 12 min	0 min	94%
Tue Dec 22	4 h 33 min	25 min	0 min	98%
Wed Dec 23	4 h 33 min	0 min	0 min	100%
Thu Dec 24	4 h 34 min	14 min	14 min	98%
Fri Dec 25	4 h 34 min	39 min	39 min	94%
Sat Dec 26	4 h 35 min	55 min	55 min	87%
Sun Dec 27	4 h 37 min	1 h 7 min	1 h 7 min	78%
Mon Dec 28	4 h 38 min	1 h 16 min	1 h 16 min	68%
Tue Dec 29	4 h 39 min	1 h 25 min	1 h 25 min	57%
Wed Dec 30	4 h 41 min	1 h 34 min	1 h 34 min	47%
Thu Dec 31	4 h 43 min	1 h 44 min	1 h 44 min	37%

Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the southern lights in Ushuaia in December?: On dark, clear nights with enough activity. 31 of 31 nights at Ushuaia have civil darkness.
How dark is Ushuaia in December?: Ushuaia averages 4.7 hours of civil night a night in December 2026, from 5 h 8 min on the 1st to 4 h 43 min on the last night.
How cloudy is Ushuaia in December?: NASA POWER's 2001 to 2020 climatology gives Ushuaia's 1 degree cell 84% mean cloud in December, against 78% for the whole year. It is an all-hours average, not a forecast.
What is the best night in December 2026 for aurora in Ushuaia?: By darkness and moon alone, Dec 1, with 3 h 12 min of moon-free darkness inside 10 PM to 2 AM at Ushuaia. Activity on that date will only be known hours ahead.
Is December or January better in Ushuaia?: By civil night times the clear share, December scores 0.7 hours at Ushuaia and January 0.9. January comes out ahead.

Sources and verification

SunCalchttps://github.com/mourner/suncalc
NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
GFZ Potsdam Kp indexhttps://kp.gfz.de/en/data
NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora

Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.